The use of S/PDIF

[jaynm26]

What are the uses of S/PDIF fiber optics and is it better than most digital I/O and why?

 

[Ethan Winer]

Optical S/PDIF is digital I/O, and so is coax (RCA connectors with wire). Fiber optic S/PDIF is good because there's no chance of ground loops. Otherwise either works equally well.

--Ethan

 

[ProToolsHelp]

S/PDIF is simply nothing more than a digital connection, v.s. the analog connections you're probably used to. Instead of analog waveforms traveling through the cable, you have 1's and 0's.

In the case of an optical connection such as "Lightpipe" or Optical S/PDIF, there is a small light that flashes on and off to represent the 1's and 0's.

If you have another device that also has S/PDIF you simply connect the output of the source device to the input of the target device. This will allow you to perform a digital transfer between the two devices. That way you wont suffer any generation loss by going back to the analog domain.

The signal that travels down the S/PDIF cable will be 2 channels of audio (left and right), plus the "wordclock" signal.

I would agree with Ethan that the lack of ground loops and EMI/RFI is a huge advantage with optical.

Make sure if you do decide to hook up two devices via S/PDIF, to designate one device as the "Master Wordclock" and resolve all other devices to that master. If you fail to do this you will likely experience clicks and pops due to clocking errors between the two devices.

Hope this helps...

 

[TimOBrien]

yup, digital is just moving around 1's and 0's. There is no 'better'; it works or it don't....

 

[Ethan Winer]

Just to clarify, a digital signal traveling down a wire is really an analog signal having two possible voltage levels that switch back and forth very quickly. There are also in-between levels for a brief period as the voltage transitions from low to high (0 to 1). An optical connection is more like pure digital where the light source is either on or off. But in practice both methods work well, and don't change the sound unless something is broken.

--Ethan

 

[mezess]

Is it so that the digital recording is not direct possible via S/PDIF input and output (and cables) with MX200 to computer and the hardware Plug-in is only to try heard different programs via monitor trought the analog outputs and if I have´t digital mixer or ny digital device in use the only choice is the analog recording via analog mixer and analog cables and devices?
-mezess

 

[TetraFish]

Is it so that the digital recording is not direct possible via S/PDIF input and output (and cables) with MX200 to computer and the hardware Plug-in is only to try heard different programs via monitor trought the analog outputs and if I have´t digital mixer or ny digital device in use the only choice is the analog recording via analog mixer and analog cables and devices?
-mezess

WOW, not sure about all of that but maybe I can clear some stuff up....

When you plug into an interface it has to convert that to a digital signal to send it to the computer and to record. So all recording you do in a computer is digital. With that being said the digital signal is only as good as the converter (inside your interface) that converted it to digital from analog.

Then when you hear the music from the speakers the computer has had to take a digital signal and convert it to analog for your speakers.

Not sure about your interface but I also have one that has a SPDIF in and out. As an example I have a guitar pedal with a SPDIF out. If I connect that to the SPDIF in on my interface I'm sending a digital signal that does not need to be converted. If I used the analog outs the signal would have to be converted to analog and then back to digital. Not sure If I can hear the difference but it stands to reason that any conversions will degredate the signal.